US20110104998A1 - Tool for polishing conventional and free-form optical surfaces - Google Patents

Tool for polishing conventional and free-form optical surfaces Download PDF

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Publication number
US20110104998A1
US20110104998A1 US12/737,393 US73739309A US2011104998A1 US 20110104998 A1 US20110104998 A1 US 20110104998A1 US 73739309 A US73739309 A US 73739309A US 2011104998 A1 US2011104998 A1 US 2011104998A1
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US
United States
Prior art keywords
polishing
resilient cushion
tool
compression
tool according
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/737,393
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English (en)
Inventor
Leonardo De Jesus Valencia Merizalde
Francisco Gonsález Alcántara
Juan Carlos Dursteler López
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Indo Internacional SA
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Indo Internacional SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Indo Internacional SA filed Critical Indo Internacional SA
Assigned to INDO INTERNACIONAL S.A. reassignment INDO INTERNACIONAL S.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: DURSTELER LOPEZ, JUAN CARLOS, GONZALEZ ALCANTARA, FRANCISCO, SAVALL FREIXINET, AGUSTI, VALENCIA MERIZALDE, LEONARDO DE JESUS
Publication of US20110104998A1 publication Critical patent/US20110104998A1/en
Abandoned legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B13/00—Machines or devices designed for grinding or polishing optical surfaces on lenses or surfaces of similar shape on other work; Accessories therefor
    • B24B13/02—Machines or devices designed for grinding or polishing optical surfaces on lenses or surfaces of similar shape on other work; Accessories therefor by means of tools with abrading surfaces corresponding in shape with the lenses to be made
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D13/00—Wheels having flexibly-acting working parts, e.g. buffing wheels; Mountings therefor
    • B24D13/14—Wheels having flexibly-acting working parts, e.g. buffing wheels; Mountings therefor acting by the front face
    • B24D13/147—Wheels having flexibly-acting working parts, e.g. buffing wheels; Mountings therefor acting by the front face comprising assemblies of felted or spongy material; comprising pads surrounded by a flexible material

Definitions

  • the present invention relates to a tool for polishing optical surfaces and to the use of such a tool when polishing optical surfaces. More specifically it relates to a tool for polishing optical surfaces comprising a rigid body carrying a resilient cushion which has a polishing face and to the use of such a tool for polishing optical surfaces.
  • a conventional type of polishing tool comprises a support which to a certain extent has a similar surface as the lens to be polished and on which a polishing pad is mounted.
  • the tool is brought into contact with the lens, and the lens surface is polished by the combined effect of a pressure between the tool and the lens and a relative angular velocity between them and with the aid of abrasive slurry.
  • the goal of the polishing process is reduce the roughness of the lens to under 10 nanometres.
  • Lenses of largely varying surfaces are known.
  • the surface of a lens may be spherical, aspherical, toric or atoric. Additionally, lenses with more irregular surfaces have been developed, so called free-forms. Free-form lenses can have largely varying surfaces containing local curvatures from 13 dioptres to 0 dioptres (a locally flat surface). When polishing these free-form lenses, the goal is not to reduce the thickness of the lens by more than 20 micrometers and at the same time obtain a surface roughness under 10 nanometers.
  • EP 1 655 102 describes using polishing tools with a rigid surface upon which an elastic body is mounted.
  • the diameter of the elastic body is between 20 and 60 mm. It is described to prepare five to ten types of elastic bodies with a radius of curvature ranging between 5 and 50 mm and several elastic bodies with a radius of curvature between 100 and 200 mm to be able to polish lenses of most lens prescriptions.
  • US 2008/0047301 describes using polishing tools which also comprise a rigid body carrying a resilient pad which has a polishing face. It also describes using 108 different devices to be able to polish a variety free-form lenses.
  • polishing tools A variety of different polishing tools is needed to be able to polish the lenses of different prescriptions. So, to polish one lens after another, the polishing tool needs to be changed. This is cumbersome and slows down the polishing process. Additionally, it is expensive to have a high number of different tools.
  • the present invention therefore aims at establishing a single polishing tool which can be used to polish a large variety of all lenses.
  • the invention aims at providing a single polishing tool that can be used for polishing conventional and free-form surfaces, which are made from any of the organic materials normally used in opthalmological lenses and with curvatures within the following curvature ranges: between 0 and ⁇ 11 dioptres sphere, between 0 and ⁇ 4 dioptres cylinder and additions up to 3.5 dioptres, with a maximum allowable (combined) local concave curvature along the surface of ⁇ 11 dioptres.
  • the lenses When they are being polished, the lenses have a round or elliptical shape.
  • the diameter of the lenses is between 50 and 70 mm.
  • the maximum difference between the diameters of the elliptical lenses is 15 mm.
  • a polishing tool comprising a rigid base which has a spherical surface which carries a resilient cushion which has a polishing face, characterised in that the diameter of the rigid base is between 50 and 65 mm, the radius of curvature of the spherical surface is between 54 and 60 mm, the thickness of the resilient cushion is between 13 and 16 mm and the resistance to compression of the resilient cushion is substantially between 0.08 and 0.15 bar at 10% compression and substantially between 0.55 and 0.8 bar at 70% compression.
  • the tool for polishing is mounted in a polishing machine and the lens is polished through a combined effect of a pressure between the tool and the lens and a relative angular velocity between them and with the aid of abrasive slurry.
  • the polishing machine may be programmed differently, i.e. the force between lens and polisher, the speed of rotation, translation etc. may be varied. With the described tool, a large variety of lenses may be polished with the same tool.
  • the polishing machine may be pre-programmed to automatically change the values of the polishing parameters (velocities, pressure etc.) depending on the curvature of the surface to be polished.
  • the resistance to compression of the resilient cushion is substantially between 0.10 and 0.16 bar at 15% compression and between 0.20 and 0.30 bar at 50% compression.
  • the resistance to compression is the parameter that describes how much the cushion deforms under pressure and thus to what extent the cushion can redistribute forces and pressures.
  • the resistance to compression is particularly relevant in the range of 15-50% compression, since this is a compression that the resilient cushion experiences mostly during polishing. A small increase in the pressure should lead to a relatively large increase in deformation (or percentage of compression). This ensures a good redistribution of forces over the lens surface.
  • the thickness of the resilient cushion is between 14 and 15 mm.
  • the resilient cushion which deforms slightly during polishing redistributes the pressure and forces on the lens surface. For this, it needs to have a certain thickness. On the other hand, if the resilient cushion is too thick, it is more likely to bend and break during polishing. With a thickness between 14 and 15 mm, a good balance of redistribution of forces and probability of breaking is achieved.
  • the radius of curvature of the spherical surface of the rigid base is between 54 and 56 mm.
  • the resilient cushion deforms to redistribute pressure and forces on the lens surface. This way, the polishing is more equal over the entire lens surface and one can ensure that the required surface roughness has been achieved while at the same time the stock removal is uniformly distributed over the surface of the lens.
  • the resilient cushion can partly redistribute forces and pressure, but this effect naturally is limited. If the curvature of the rigid base corresponds more closely to the curvature of the lens surface that is to be polished, the forces do not need to be redistributed as much.
  • the diameter of the rigid base is between 55 and 65 mm.
  • the larger the diameter of the tool the higher the velocity at its extremity in rotation and this leads to more material removed in the polishing process.
  • the necessary linear movement of the tool in polishing is reduced, since with a small movement it already covers the entire surface of the lens. This reduces polishing time.
  • a diameter between 50 and 65 mm satisfactory results are achieved, but improved results are achieved with diameters between 55 and 65 mm.
  • the resilient cushion is a sponge, commercially available as Eurocell 130TM from Recticel.
  • This sponge is made from polyether, has the required resistance to compression and a specific density between 110 kg/m 3 and 130 kg/m 3 .
  • the polishing face of the resilient cushion is formed by a separate polishing pad which can be attached to the resilient cushion.
  • the separate polishing pad may be attached to the resilient cushion using an adhesive.
  • the polishing pads and resilient cushions can thus be manufactured separately which is easier.
  • the polishing pad comprises a top layer and a bottom layer, the top layer being a nap layer adapted to carry an abrasive slurry.
  • the bottom layer of the polishing pad is of a polyurethane impregnated non-woven fabric.
  • the function of the polishing pad is to hold the abrasive slurry and bring it into contact with the lens.
  • the pad with these characteristics has been shown to function properly and also to last long. With other polishing pads, the pad needs to be changed more frequently, which is costly and slows down the polishing process.
  • polishing pads have the desired characteristics.
  • suitable pads are: Bellatrix Polishing PAD K0034TM commercially available from Filwel Co., Ltd. and PolitexTM Supreme finishing pad, commercially available from EMINESS technologies Inc.
  • the abrasive slurry used may be an aluminium oxide water solution.
  • FIG. 1 is a cross section showing a polishing tool according to a preferred embodiment of the present invention, with its components shown separately;
  • FIG. 2 is a cross section showing a polishing tool according to a preferred embodiment of the present invention in use
  • FIG. 3 is a perspective view of a polishing pad which might be used in the invention.
  • FIG. 4 a shows a graph of the resistance to compression of a resilient cushion which may be used in the present invention
  • FIG. 4 b shows a detail of the graph shown in FIG. 4 a.
  • FIG. 1 it is shown how a polishing tool according to a preferred embodiment of the present invention is built up from its separate components.
  • a first component is the rigid body ( 11 ).
  • Rigid body ( 11 ) comprises a surface ( 14 ), upon which resilient cushion ( 12 ) is to be mounted.
  • the polishing face of the resilient cushion is formed by a polishing pad ( 13 ).
  • Reference sign ( 15 ) is used to indicate the side of the rigid body ( 11 ) which is to be mounted in the polishing machine.
  • the surface ( 14 ) is spherical and has a radius of curvature between 54 and 60 mm.
  • the diameter of the tool is between 50 and 65 mm, and the thickness of resilient cushion ( 12 ) is between 13 and 16 mm.
  • the resilient cushion has a resistance to compression between 0.14 and 0.4 bar when compressed between 15% and 60%.
  • FIG. 2 shows a schematic cross section of polishing tool ( 10 ) completely assembled with rigid body ( 11 ), resilient cushion ( 12 ) and polishing pad ( 13 ).
  • the top surface ( 16 ) of the polishing pad is used to polish the surface ( 21 ) of a lens ( 20 ) and can be regarded as the polishing face of the tool.
  • the lens surface that is to be polished ( 21 ) does not exactly correspond to the surface ( 16 ) of the polishing tool. In fact, it can be quite different, since a wide range of lenses (between 0 and ⁇ 11 dioptres sphere, between 0 and ⁇ 4 dioptres cylinder and additions up to 3.5 dioptres, but with a maximum allowable combined local concave curvature along the surface of ⁇ 11 dioptres) is polished with the same tool.
  • the resilient cushion ( 12 ) deforms when in contact with the lens. This ensures a redistribution of forces over the surface ( 16 ) of the lens. This ensures that the desired roughness and an even stock removal can be obtained over then entire surface.
  • the tool is the same for the whole range of lenses, but the program that the polishing machine performs can vary.
  • Some parameters of the polishing program may be e.g. rotational velocity ( ⁇ 1 ) of the tool, rotational velocity ( ⁇ 2 ) of the lens, lateral displacement and velocity (v) of the tool, inclination between the axis of the tool and the axis of the lens, force between lens and polisher and polishing time.
  • FIG. 3 shows a perspective view of a polishing pad ( 13 ) which might form the polishing surface ( 16 ) of a tool according to the invention.
  • the bottom surface ( 19 ) may carry an adhesive to easily attach it to the resilient cushion.
  • the polishing pad shown has two layers.
  • a top layer ( 17 ) is designed to hold an abrasive slurry. For this purpose, it preferably has vertical pores.
  • the abrasive slurry used may be an aluminium oxide water suspension.
  • the bottom layer ( 18 ) is preferably of a non-woven fabric.
  • FIG. 4 a shows a graph of the resistance to compression of a resilient cushion which may be used in the present invention.
  • the graph shows the resistance to compression of the cushion Eurocell 130TM commercially available from Recticel.
  • the resistance to compression is particularly relevant in the range of 15-50% compression, since this is a compression that the resilient cushion might ordinarily experience during polishing.
  • a small increase in the pressure leads to a relatively large increase in deformation (or percentage of compression). This ensures a good redistribution of forces over the lens surface.
  • FIG. 4 b shows a more detailed view of the lower range of compression.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
  • Polishing Bodies And Polishing Tools (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
US12/737,393 2008-07-08 2009-07-07 Tool for polishing conventional and free-form optical surfaces Abandoned US20110104998A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EPEP08382026.6 2008-07-08
EP08382026A EP2143527B1 (de) 2008-07-08 2008-07-08 Werkzeug zur Reinigung konventioneller und frei geformter optischer Oberflächen
PCT/ES2009/000355 WO2010004065A1 (es) 2008-07-08 2009-07-07 Herramienta para el pulido de superficies ópticas convencionales y de formas libres

Publications (1)

Publication Number Publication Date
US20110104998A1 true US20110104998A1 (en) 2011-05-05

Family

ID=39876258

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/737,393 Abandoned US20110104998A1 (en) 2008-07-08 2009-07-07 Tool for polishing conventional and free-form optical surfaces

Country Status (7)

Country Link
US (1) US20110104998A1 (de)
EP (1) EP2143527B1 (de)
JP (1) JP2011527242A (de)
AT (1) ATE494985T1 (de)
DE (1) DE602008004494D1 (de)
ES (1) ES2359283T3 (de)
WO (1) WO2010004065A1 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150105002A1 (en) * 2013-10-16 2015-04-16 Carl Zeiss Vision International Gmbh Tool for the polishing of optical surfaces
US20170246729A1 (en) * 2014-10-15 2017-08-31 Satisloh Ag Polishing disc for a tool for fine processing of optically effective surfaces on spectacle lenses
US20210016410A1 (en) * 2019-07-16 2021-01-21 Schneider Gmbh & Co. Kg Polishing tool and device for polishing a workpiece

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4707949A (en) * 1985-07-26 1987-11-24 Optimed N.V. Method for manufacturing a spectacle-glass for myopes
US5140782A (en) * 1990-10-29 1992-08-25 Honore Mecteau Tool and method for forming a lens
US20080047301A1 (en) * 2004-08-03 2008-02-28 Indo Internacional, S.A. Tool and a Method for Polishing Optical Surfaces
US7503834B2 (en) * 2004-01-15 2009-03-17 Carl Zeiss Vision Gmbh Apparatus and a method of polishing an optical surface; an optical component; and a method of manufacturing a polishing tool

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3787457B2 (ja) * 1999-05-10 2006-06-21 キヤノン株式会社 研磨工具
FR2823143B1 (fr) * 2001-04-10 2003-07-04 Essilor Int Outil torique de polissage d'une surface optique d'une lentille, et procede de polissage d'une surface atorique au moyen d'un tel outil
EP1655102B1 (de) 2004-11-09 2008-01-09 Seiko Epson Corporation Elastisches Polierwerkzeug und Verfahren zum Polieren einer Linse mit einem solchen Werkzeug

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4707949A (en) * 1985-07-26 1987-11-24 Optimed N.V. Method for manufacturing a spectacle-glass for myopes
US5140782A (en) * 1990-10-29 1992-08-25 Honore Mecteau Tool and method for forming a lens
US7503834B2 (en) * 2004-01-15 2009-03-17 Carl Zeiss Vision Gmbh Apparatus and a method of polishing an optical surface; an optical component; and a method of manufacturing a polishing tool
US20080047301A1 (en) * 2004-08-03 2008-02-28 Indo Internacional, S.A. Tool and a Method for Polishing Optical Surfaces

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150105002A1 (en) * 2013-10-16 2015-04-16 Carl Zeiss Vision International Gmbh Tool for the polishing of optical surfaces
US9409274B2 (en) * 2013-10-16 2016-08-09 Carl Zeiss Vision International Gmbh Tool for the polishing of optical surfaces
US20170246729A1 (en) * 2014-10-15 2017-08-31 Satisloh Ag Polishing disc for a tool for fine processing of optically effective surfaces on spectacle lenses
US10569387B2 (en) * 2014-10-15 2020-02-25 Satisloh Ag Polishing disc for a tool for fine processing of optically effective surfaces on spectacle lenses
US20210016410A1 (en) * 2019-07-16 2021-01-21 Schneider Gmbh & Co. Kg Polishing tool and device for polishing a workpiece

Also Published As

Publication number Publication date
EP2143527A1 (de) 2010-01-13
JP2011527242A (ja) 2011-10-27
DE602008004494D1 (de) 2011-02-24
WO2010004065A1 (es) 2010-01-14
ATE494985T1 (de) 2011-01-15
ES2359283T3 (es) 2011-05-20
EP2143527B1 (de) 2011-01-12

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AS Assignment

Owner name: INDO INTERNACIONAL S.A., SPAIN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:VALENCIA MERIZALDE, LEONARDO DE JESUS;SAVALL FREIXINET, AGUSTI;GONZALEZ ALCANTARA, FRANCISCO;AND OTHERS;REEL/FRAME:025633/0967

Effective date: 20110107

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION